Multiple accounts are supported, but each user has their own apps. If there are multiple users on a Surface and at least one of them has a Microsoft account, apps for the Microsoft account can be shared with as many as four additional users (five total).

You can install free or purchased apps to each account on the same Surface device without repurchasing. The user has to sign into Surface, go to Store, once in Store switch to the Microsoft account by opening the Charms and under Settings select 'Your Account". Store will ask you to login, once you do then simply find the apps you have previously paid for and installed under the Surface Microsoft account and install the apps for that Surface user, then open the Charms and under Settings select 'Your Account", click sign out and that returns the Store Settings to revert back to the Surface user account.

You would repeat this process for each user. Please note that many of the Microsoft apps require you to login with a Microsoft account in order to use them.